Hm, indeed. Here’s a zoomed version, with a relative error graph. Even at small angles, it’s correct to within better than 5%, and for its implied domain of inputs greater than 1, its worst behavior is only about 0.1% (at an input of around 5). Which might actually be useful in some contexts. Which, in turn, leads one to wonder why its proponents make it deliberately hard to use and understand, by writing it out using Sanskrit characters for the variables.
Yeah, I found that bizarre as well. Also slightly odd that it’s presented in terms of short/medium/long sides, even though the third is determined by two of the others. In my graph above I held the S side fixed at 1, computed L, and let M be the variable.
It’s an interesting enough approximation that I might try to see why it’s as good as it is. I have a trip coming up and it might be an interesting diversion on the plane.
Mr. Bibhorr Astrr is certainly an … interesting … character. I wonder if Mr. Timecube started out this way?
There’s a large population who might find the Sanskrit characters no more difficult to use than Indo-Arabic numbers - but I suspect the main reason is signaling Indian-nationalism. The hyperbole about the usefulness of this formula is offputting. It’s not like Bibhorr has invented Tai’s model
Oh my. Didn’t think to search for this Bibhorr as a person.
Bibhorr is the Founding Aerospace Engineer at Bibhorr Astrr (2023) and the Founding Cosmic Weaponry Scientist & Intergalactic Military Anthropologist at Bibhorr Aerospace Labs (2014). He is the Vanguard Leader of Ultra-Futuristic Aerospace and Defense Boom.
Now I want to be a Cosmic Weaponry Scientist and Intergalactic Military Anthropologist.
Ah, they’re 1920s style death rays.
I’m thinking being named Vanguard Leader would be pretty cool.
Unless I’m the guy naming myself. In which case I’ve outed myself as an insufferable douchebag.
Oddly the History Channel and such love to blather on about “Tesla’s 'secret death ray!!!”- but Tesla never called it that or claimed it would kill- it would just incapacitate an aircraft- which i guess might lead to a crash and deaths, but he strongly opposed calling it that. (a good number or even most of aircraft from that period (late 1920s) could glide to a sorta kinda safe-ish crash landing if the engines cut off, but not so modern jets)
I just saw one that was the basis of a Family Guy joke:
A lot of people mock the refrain
“Oh Romeo, Oh Romeo, wherefore art thou Romeo?”
With the reply “I’m right here!”
Well, actually
“Wherefore art thou”is asking “why are you Romeo?” (I.e. why can’t you be somebody with a different name? A rose with another name would still smell as sweet) not “Where are you Romeo”
Which is why she wants him to change his name or she will.
I can’t believe that site didn’t mention the Gimli Glider (Air Canada flight 143), probably the most famous example of a jetliner gliding some distance and landing safely.
Okay, i wont argue that some modern jets can glide. But compare those to the late 1920’s planes- many still biplanes.
Sill the “death ray” wasnt.
All modern jets can glide. In fact, per the article I linked to, that’s what they are doing during the descent from cruising altitude when getting ready to land:
The chances are that if you’ve flown on a plane, it will have been gliding during the descent when the engine is commanded by the pilots to produce very little thrust/power. For most of the descent, the engine is running at ‘idle’ (minimum thrust) – it maintains it’s forward airspeed by descending.
Wasn’t that why the gyrocopter was invented?
And didn’t the vanguard protect the rear? The leading units were the avant garde.
I hereby dub thee Vanguard Leader.
There you go - you’ve been appointed, and you didn’t have to name yourself.
May, indeed, be among the best aircraft at it that were not purpose-built to be gliders—designed as they are with modern knowledge of aerodynamics and modern focus on efficiency. Also, helped by not having an airbrake where your engine used to be, in the case of a dead prop-driven aircraft with straight, high-drag, pre-NACA “try it and see what works” airfoils. The lift/drag ratio of a Curtiss JN-4 is a lot closer to that of a Cessna 172 (L/DMAX of 10.9—page 12 here (PDF)) than the 15+:1 lift-drag ratios given here for modern airliners as a proxy for glide ratio.
This is true for many military aircraft as well, even though they were not as such designed for maximum fuel efficiency; subsonic L/DMAX for e.g. the F-14 is given by NASA here as 15 also, citing this presentation. See also the Israeli F-15 that landed without its right wing (and was repaired and returned to service), or the F-106 that landed itself after its pilot ejected (…and was repaired and returned to service).
The problem with gliding jets isn’t so much whether they glide (they do) and whether they have decent glide ratios (they do).
The problem is the speed involved. Kinetic energy goes at the square of the speed, and all that energy needs to be dissipated to zero to get the plane / wreckage stopped.
For very round numbers:
An ancient biplane glides best at 40mph. A modern Cessna glides best at 65 mph. An old DC-3 propliner glides best around 100mph. A modern Boeing glides best around 150mph and more like 200 with no flaps. An F-16 glides best at 300mph.
All of which is just fine until you first touch the ground or water going that fast. Finding a spot of land empty enough and flat enough to survivably decelerate from 40 or 60 mph is rather different than from 150 mph or 300.
Biplanes and Cessnas also have fixed wheels that are designed to handle landing on rough surfaces. Which generally means they can slow down somewhat from glide speed before the “landing” becomes a “crash landing” when something breaks and the whole thing comes to an abrupt stop. Conversely, in any of the bigger / faster machine, first contact with the ground/water is when stuff starts breaking. which sets up an abrupt high-G stop from a much higher speed.
I was just reminded of an example that I’ve been guilty of pedantry over in the past…using ‘less’ instead of ‘fewer’ when describing an easily quantifiable noun. For example, one might have less water, but fewer bottles of water.
But I’ve since learned (from the SDMB as a matter of fact, among other sources) that using ‘less’ as in ‘I have less bottles of water than I had yesterday’ is perfectly cromulent usage. Still sets my teeth on edge whenever I hear or read ‘less’ used that way.